To everyone’s amazement, especially considering the dire predictions of a long winter, summer-like weather is already upon us. Maybe it’s just a short-term glitch, but warm unseasonable weather is spawning a great deal of thunderstorms in rare locations. For pilots, airline operations, ATC, and passengers, thunderstorms are a frustrating reality of summer time flying. With the undue arrival of fowl weather, I’d like to shed some light on what makes these storms such a problem for all things aviation as well as how it directly affects you, the passenger.
Thunderstorms are an airplanes worst enemy. Meteorologically speaking, thunderstorms are a result of the lifting of warm, moist air. As the air rises, it cools condenses into a cloud. As the droplets of water collide with each other, they grow and eventually fall in the form of rain. This rainfall causes downdrafts of air that hit the ground and spread out laterally. Downdrafts pose a large threat to aircraft in the form of wind shear. Aircraft and airports have equipment that detects wind shear and warns pilots of its presence. If the aircraft equipment detects a wind shear situation, it directs the pilots with visual cues to avoid it.
The rising of air that results in a storm is the result of a lifting force. This force can be the result of a weather front or warm air rising on its own. A cool air mass often results in the most severe thunderstorms, named squall lines. As cool air overtakes a warm air mass, it forces the warm air to rise rapidly into the atmosphere, causing severe storms. Such storms typically grow on a massive scale and move laterally across a region with great speed. Air-mass thunderstorms on the other hand, are a result of rising warm air, typically on a hot summer afternoon. They don’t move laterally like squall lines, but instead form all over the place like popcorn. These storms build and dissipate quickly compared to squall lines. Both types of storms have the ability to grow vertically on a massive scale, often reaching more than 60,000 feet. The rapidly rising air that builds the storms causes severe turbulence, and often spews out hail near the storm. Lightning is another factor at play, and aircraft are frequently struck. The good news is that airplanes are designed to withstand lightning strikes and usually it’s a non-event when it happens.
Aircraft must avoid thunderstorms as well as the surface conditions they produce. In terms of wind shear, pilots avoid both taking off and landing during such conditions. Often the passage of a storm near or over an airport causes operations to grind to a halt. For aircraft attempting to take off, a tarmac delay can result until the storm passes. Returning to the gate is not usually possible either, as ground personnel are not allowed on the ramp when lightning is present. That means there’s nobody available to marshal an airplane into the gate, let alone to retrieve baggage. For aircraft attempting to land, an airport closure results in aircraft holding pattern assignments. Of course flights can only hold for so long with fuel endurance becoming an issue. When holding is no longer possible, and the destination airport is still closed, the pilots are forced to divert to an alternate airport to refuel and wait out the storm. If you have a connecting flight, chances are your connecting aircraft is in the same situation and therefore there’s still hope that you won’t be stranded.
Aside from threats to the airport directly, thunderstorms can also pose threats to aircraft en route to a destination. As mentioned in previous articles, a storm acts like a broken down car causing a freeway backup. As aircraft veer off course to avoid a storm, they may interfere with the path of other flights, causing aircraft spacing to be reduced. If spacing is reduced too much, ATC must slow the pace of traffic down to accommodate aircraft that are deviating around a storm. If you’re on the ground waiting to take off and your flight is slated to occupy one of those congested routes, ATC may hold you on the ground until there is room for your flight. This often results in a tarmac delay.
Storms tend to form in various places and/or move to a new location, and as such they create a very dynamic and frustrating situation for ATC. Long delays can result. A solid line of impenetrable storms, such as a squall line, will often force a flight to deviate significantly from its ideal routing. Airline dispatchers will plan flights to avoid these storms, and could result in an additional hour or more to the original planned flight time.
It’s hard to predict if you flight will be affected by such weather well in advance. My best advice for those travelers slated for flights during the summer months is to keep your eye on weather reports. The day before, or the morning of your afternoon flight, watching weather reports can be a good indicator of what airports will be facing weather delays. And remember, just because the weather at your departure and arrival airport looks good, doesn’t mean you’ll be on time. Weather nearby or in-between you and your destination can pose a threat. If getting to point ‘B’ is crucial, consider working with the airline to change your departure time or connection airport. Connecting through another city away from the forecasted storms could mean a longer trip and a change fee, but may result in a far less stressful trip. Although storms associated with weather fronts can form day or night, the more typical hot summer day storms tend to form in the afternoon. Knowing this, I always plan my personal travel during the summer months to take place early in the morning, long before storms begin to form. That’s my best advice.
As you approach the summer months with travel plans, although frustrations are inevitable, understand that your safety is paramount. That’s the bottom line and always will be. Plan accordingly and keep apprised of the situation across the country with the invaluable information provided right here on the FlightAware website. Thanks for reading and safe travels!